Bandwidth-enhanced of a very simple circularly polarized square slot antenna with offset feed and modified ground plane

Author(s):  
Jie Liu ◽  
Jian-ying Li ◽  
Rui Xu ◽  
Du-Juan Wei
2019 ◽  
Vol 11 (10) ◽  
pp. 1054-1060
Author(s):  
Kapil Saraswat ◽  
A. R. Harish

AbstractA polarization and band reconfigurable cross-slot antenna for multiband applications is presented in this paper. The antenna consists of four p–i–n diodes embedded in the cross-shaped slot in a ground plane and excited by a microstrip feed line. The p–i–n diodes are placed in such a way that they produce multiple bands, with linearly and circularly polarized (CP) radiation. By switching the states of the p–i–n diodes, the sense of rotation of the electric field in CP radiation can be reconfigured. The proposed structure can be configured to produce two bands that radiate linearly polarized waves or three bands, where, two are linearly polarized and one is CP. The proposed design concepts are validated bythe CST studio suite as well as measurementsare carried out on fabricated prototypes.


2016 ◽  
Vol 9 (3) ◽  
pp. 649-656 ◽  
Author(s):  
Neng-Wu Liu ◽  
Lei Zhu ◽  
Wai-Wa Choi

A low-profile circularly polarized (CP) slot antenna to achieve a wide axial-ratio (AR) beamwidth is proposed in this paper. The radiating patch consists of two orthogonal pairs of parallel slots etched symmetrically onto a ground plane. Firstly, our theoretical study demonstrates that the CP radiation can be satisfactorily achieved at the broadside, when the vertical and horizontal paired-slots are excited in the same amplitude with 90° phase difference. Secondly, the principle of CP radiation of the proposed antenna on an infinite ground plane is described. Through analyzing the spacing between two parallel slots, the |Eθ| and |Eφ| radiation patterns can be made approximately identical with each other over a large angle range. As such, the slot antenna achieves a wide AR beamwidth. After that, the 3 dB AR beamwidth with respect to the size of a finite ground plane is investigated to constitute a practical CP antenna on a finite ground plane. In final, the proposed CP antenna with a 1–4 probe-to-microstrip feeding network is designed and fabricated on a finite ground plane of a dielectric substrate. Measured results are shown to be in good agreement with the simulated ones about the gain, reflection coefficient, AR bandwidth, and radiation patterns. Most importantly, a wide 3 dB AR beamwidth of 126° and low-profile property with the height of 0.036λ0 are achieved.


2018 ◽  
Vol 11 (2) ◽  
pp. 182-189 ◽  
Author(s):  
Shilpee Patil ◽  
Anil Kumar Singh ◽  
Binod Kumar Kanaujia ◽  
R. L. Yadava

AbstractThis paper presents a compact microstrip antenna using FR-4 substrate for dual band circularly polarized operation using a modified square ring slot in the ground plane with microstrip line feed. Simulation of the impedance characteristic and radiation characteristic for the proposed antenna is carried out using commercially available HFSS software. The simulated data validate measured results and shows good agreement. Proposed antenna shows an impedance bandwidth (return loss >10 dB) of 50.88% at 5.9 GHz of center frequency and 29.92% at 12.8 GHz of center frequency for lower and upper band, respectively. The 3 dB axial ratio bandwidth for lower and upper band is 26.4 and 3.0%, respectively and measured peak gain for the lower and upper band is found as 3.2 and 3.4 dBic, respectively. The proposed antenna can be suitable for wireless communication in C and Ku bands.


2018 ◽  
Vol 7 (5) ◽  
pp. 1-6 ◽  
Author(s):  
A. R. Parvathy ◽  
V. G. Ajay ◽  
M. Thomaskutty

A compact circularly polarized printed slot antenna operating at 2.45 GHz is reported. The antenna consists of a pair of rotated square split ring resonators (SRR) inside a rectangular slot etched on the ground plane of an FR-4 dielectric substrate. A microstrip open-loop feed is etched on the backside of the dielectric substrate to feed the slot and the split ring resonators. The overall size of the antenna is 60x42x1.6 mm3. The measured -10dB impedance bandwidth is 10.48% (2.38-2.64 GHz) and the measured 3dB axial ratio (AR) bandwidth covers the entire impedance bandwidth.


Frequenz ◽  
2018 ◽  
Vol 72 (7-8) ◽  
pp. 333-341 ◽  
Author(s):  
Qiang Chen ◽  
Hou Zhang ◽  
Lu-chun Yang ◽  
Bin-bin Li ◽  
Xue-liang Min

Abstract A design with wideband and circularly polarized radiation antenna from an open-slot antenna has been demonstrated in this paper. The proposed antenna, which consists of an open slot and an inverted-L strip feeding, provides a large bandwidth, which completely cover the Wimax (3.3–3.8 GHz) and WLAN (2.4–2.48 GHz) bands. The open slot is formed by an modified ground plane with a slit cut and monofilar spiral stubs employed, which fed by an asymmetrical inverted-L strip feedline using a via. As demonstrated, the CP operation was significantly improved by loading monofilar spiral stubs connected to the asymmetric feedline by means of a via. A parametric study of the key parameters is made and the mechanism for circular polarization is described. After optimization, the impedance bandwidth is approximately 3.78 GHz (2.12 to 5.9 GHz) and the 3 dB axial ratio bandwidth is approximately 2.75 GHz (2.2 to 4.95 GHz), which represent fractional bandwidths of approximately 94.3 % and 76.9 %, respectively.


Frequenz ◽  
2018 ◽  
Vol 72 (5-6) ◽  
pp. 181-188
Author(s):  
Chien-Yuan Pan ◽  
Chum-Chieh Su ◽  
Wei-Lin Yang

Abstract A new circularly polarized (CP) slot antenna with a small gap and a stick-shaped shorted strip is presented. The proposed antenna has a sufficient bandwidth for ultrahigh frequency (UHF) radio-frequency identification (RFID) reader applications. The antenna structure consists of a rectangular slot with a small gap, a stick-shaped shorted strip and a 50 Ω coplanar waveguide (CPW) feedline with an asymmetrical ground plane. By using the stick -shaped shorted strip to disturb magnetic current distribution on the slot, the CP radiation can be generated. The measured results demonstrate that the proposed antenna can reach a 10 dB return loss impedance bandwidth of 14.1 % (894–1030 MHz) and a 3 dB axial ratio (AR) bandwidth of 6.4 % (910–970 MHz). The whole antenna size is 80 × 80 × 1.6 mm3.


2019 ◽  
Vol 8 (4) ◽  
pp. 2133-2139

A miniaturized microstrip-fed, wideband and circularly polarized L-shaped slot antenna is designed for ultra-wideband applications. To realize L-shaped slot antenna with wide impedance bandwidth, a stub of size 10.7 mm2 is added to a rectangular shaped slot of the ground plane. The position of the feedline is optimized to attain wide circular polarization bandwidth. The proposed antenna size is very small i.e., 25×25 mm2 . A prototype of the design is fabricated and measured. The axial ratio bandwidth (ARBW< 3 dB) of 2.2 GHz (from 6.2 GHz to 8.4 GHz) and the impedance bandwidth (S11<-10 dB) of 7.4 GHz (from 2.5 GHz to 9.9 GHz) is achieved by the proposed design. Moreover, the antenna achieves a stable radiation pattern and a gain of more than 2.8 dBi over the complete ARBW. The advantages of the structure are miniaturized design, having wide impedance bandwidth, and broad ARBW


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